Modded 2C M@g, (2cM61), 1331 Torch-Lumens

Northern Lights · Dec 19, 2006

The ROP LE originally claimed maybe the brightest in the smallest package hotwire and that is only about 600 torch-lumens, I quote:

"At this time I believe this may be the brightest 2C mod available. Please correct me if I'm wrong".-10-15-2005

https://www.candlepowerforums.com/threads/95327

Phillips 5761 available from several vendors looked like it could beat the 600 Torch-lumens of the Pelican bulb on 7.2 volts. Plugging the 5761 parameters into Welch Allyn equations you get this:

(spread sheet, courtesy of AWR's Hot Rater spread sheet bulb calculator!)

The problem in attempting this in a 2C size in the past has been the limited battery capacity; out of the 7.2-volt bulbs like the wa1111 and others the Pelican was the brightest available that would not over draw more than 2c, which is a problem with lithium batteries I am told.

941 Lumens goes out the front end. The lamp runs hot, 5.53 amps so with 18650's 2600 mAh you are pushing the issue just over the 2c draw, but you are close. With AW's new lithium C coming out it has potential. The 2600 mAh I got from BatterySpace.com. Calculations put the run time at 28 minutes, if you figure on AW's expected 3.3 Ah batteries you may get 35 minutes run time. The anticipated cost means that extra 6-7 minutes could costs about $20.

Well, my light is a working light and needs to go into service now, so I could not wait for the C lithiums but I can always build another or change when they come out. So I put together my 2CM61 using a UCL window, Litho123 SMO reflector, Phillips 5761, which BTW are .377 like the Pelican in diameter, FIVEMEGA PR>Bi-pin socket, two BatterySpace 18650, 2600 mAh. I also reworked the switch direct jumping the connections reducing the resistance and locking the slug down for focal point correction. The tail cap spring was replaced with an o-ring of the right thickness to snub the batteries that ride in a section of rubber hose. The tail cap snub is wrapped with three loops of de-solder copper braid. Tomorrow I will de-anodize the bezel and tail cap exteriors and polish them. These two areas get scratched the most and bright aluminum does hide those nicks.

It has a great beam pattern and works out better than my Mag Charger which is now a MC61.

FIVEMEGA's socket and one of his cammed smooth reflectors would fit perfectly to a particular job I have for this light. If only I could find the reflector.

This light cost $99 to make, changing to another socket and window I could get it down to @ $85 total.

Thanks to the posts and PMs from (and if I go up in smoke it is because I didn't listen to them!):

Alin10123
Litho123
FIVEMEGA
andrewwynn-AWR

LumenHound · Dec 19, 2006

Re: Modded 2C M@g, (2cM61), 941 Torch-Lumens

A pair of 3.3AH rated cells might not provide enough grunt to keep the cell voltage up at 7.1~7.2 for reasonable amount of time with the 6 volt 30 watt 5761.

It's a hungry bulb.

I'm looking forward to seeing what the various discharge curves of this upcoming battery are like.

How many seconds do your 2600mAH rated 18650's hold the voltage at 7.2 at the bulb?

Bob_G · Dec 19, 2006

Re: Modded 2C M@g, (2cM61), 941 Torch-Lumens

awr said he blew one in a few seconds running at 7.2V off a bench supply. I run mine off 2S3P 17670, with a hotdriver purchased complete as a 7.2V, and it was 7.14 at the pins when I checked it once on partially used cells. I don't know how he sets them though - if he's using a bench supply, then there'd be a bit of a cushion for the end user I'd think (assorted resistances from batter holder and whatnot.)

missionaryman · Dec 19, 2006

Re: Modded 2C M@g, (2cM61), 941 Torch-Lumens

got a beamshot next to ROP high or MAG85?

Northern Lights · Dec 19, 2006

Re: Modded 2C M@g, (2cM61), 941 Torch-Lumens

No beam shot yet, busy week, I have an ROP around here. Like many folks, ROP was my first, then I got the taste for more light and began to experiment. The ROP is now on 6D NiMh, FM SMO reflector, frosted lamp, gave it to a neighbor, his host in the first place, looks like a bazooka.

Northern Lights · Dec 19, 2006

Re: Modded 2C M@g, (2cM61), 941 Torch-Lumens

Beam shot. No need for me to do it. 1185 brighter than an ROP, 5761 brighter than a 1185! Done very well by others. This is what convinced me, work done by these and other members.

ROP v. 1185
https://www.candlepowerforums.com/threads/110592&highlight=rop+1185
1185 v. 5761
https://www.candlepowerforums.com/threads/127925&highlight=5761

missionaryman · Dec 20, 2006

Re: Modded 2C M@g, (2cM61), 941 Torch-Lumens

great thanks

Lips · Dec 20, 2006

Re: Modded 2C M@g, (2cM61), 941 Torch-Lumens

Northern Lights said:
Beam shot. No need for me to do it. 1185 brighter than an ROP, 5761 brighter than a 1185! Done very well by others. This is what convinced me, work done by these and other members.

ROP v. 1185
https://www.candlepowerforums.com/threads/110592&highlight=rop+1185
1185 v. 5761
https://www.candlepowerforums.com/threads/127925&highlight=5761

Here's a:

FiveMega Chrome 2D running 5761 instead of ROP bulb that came with it.

6 X 17500 (1100mah cells) in 2s3p setup

More light than the ROP HOLA was putting out but seems a little underdriven. Not as much light as Mag85 or 1500L - 1164 in this setup.

Gonna do a tailcap spring mod and tower spring to see if it gets whitter light...

.

missionaryman · Dec 20, 2006

Re: Modded 2C M@g, (2cM61), 941 Torch-Lumens

I recall FM saying you should remove resistance in stages and test the light as you go so as to not instaflash the bulb.

Northern Lights · Dec 20, 2006

Re: Modded 2C M@g, (2cM61), 941 Torch-Lumens

missionaryman said:
I recall FM saying you should remove resistance in stages and test the light as you go so as to not instaflash the bulb.

I just insta-flashed a bulb in the light I posted about here after improving even more this spring replacement solution:
https://www.candlepowerforums.com/threads/143345
The bulb had 30 minutes on it, the batteries were fairly fresh off the charger. I place into the tail cap the snubber built on flat rubber washers in lieu of an o-ring and gave it a better amount of copper braid to contact. The one-two punch got me.

FM is a great source of experience and advice.

missionaryman · Dec 20, 2006

Re: Modded 2C M@g, (2cM61), 941 Torch-Lumens

So can anyone send me a few of these lamps if I paypal them? It's just too hard to try and buy one in Australia with minimum quantities for international shipping or US retailers who will only use UPS (delivery US$65 for a light bulb!).

bwaites · Dec 20, 2006

Re: Modded 2C M@g, (2cM61), 941 Torch-Lumens

The problem is that 6 cells, whether 14500's in series/parallel, or NiMh will hold voltage better than 2 cells, (2x18650), so the 5761 might not be as bright as the ROP if the voltage sags.

That said, I'm trying to get a few to give it a try!

Bill

Northern Lights · Dec 24, 2006

Re: Modded 2C M@g, (2cM61), 941 Torch-Lumens

I took real live measurements with my trusty Digital Multi-Meter:
The batteries were charged and let rest 12 hours, approximately 12 minutes of burn time was accumulated then rested 12 more hours, 24 total since last charge. These are the readings from the 2CM61, 2C size Maglight Host:

two BatterySpace 18650, 2600 mAh batteries, I measured under 2300, averaging 2200 mAh but remember these already have been run some. (the vendor carries 2200, 2400 and these 2600s, I wonder what the other two really measure) These batteries are discussed in another thread and appear only to have short circuit protection.

Voltage on the bulb:7.95 volts
Amperes under operation: 5.24
Watts: 40.1
Bulb life:3.4 hours

Plug these numbers in and the chart posted is not correct now but the results are a whopping 2048 bulb-lumens, 1331 TORCH-LUMENS.
Bulb life is 3.4 hours, that explains the insta-flash for batteries hot off the charger. I understand, I hope correctly, that lithium batteries do not hold over voltage as well as NiMh but this is enough to zap the 5761. The equations in the calculator are the ones from the Wellch Allyn site and by many othres threads I see they are accepted generally by most experienced builders. All I knew is it did not look like expected, it was much brighter than expected when compared to other parameters I had available.

Undoubtedly the voltage will drop down to the 7.2-7.1V optimum range with a little more run time before charging again, maybe after all they can be considered to be unprotected cells. But on 7.1 volts it still should be 896 torch-lumens.
Truly yours,
Blinded by the Northern Lights, <*,)}}}}><

LumenHound · Dec 24, 2006

I'll ask again...what voltage under load with that bulb did you get after 90 seconds???

How is it that you can run a bulb that draws more than 5.5 amps continuous from a set of 18650 2600aH cells?

How is it that your cells don't fold when you run that bulb for more than 30 seconds???

What are you readings after one minute???

I'm not saying your batteries are way better than what everyone else has, I'm just saying I have to wonder???

There is no way a set of 18650's will hiold 7.95 volts on a 5.5 amp draw.
Your lucky to get 7.4 volts.
7.2 would be more like it.

LumenHound · Dec 24, 2006

double post, same as above. sticky keyboard.

Northern Lights · Dec 24, 2006

LumenHound said:
I'll ask again...what voltage under load with that bulb did you get after 90 seconds???
How is it that you can run a bulb that draws more than 5.5 amps continuous from a set of 18650 2600aH cells?
How is it that your cells don't fold when you run that bulb for more than 30 seconds???QUOTE]
I wonder too. The theoretical equations show this bulb pulling 39 watts and I measure enough amps through it to say that is reasonable my numbers give it 40.1 watts. I never have run it for more than maybe 4 minutes at a time. Now I am scared to do that since I took those measurements. I new I was pushing the 2c draw and was over. This should not work. The batteries are knew. I have played with the light a week now every day for a cumulative time up to about 20 minutes on the charge. Then I recharge the batteries. Right now they are on a pack charger and when they get off I will put each seperately through again and after at least four hours of rest I will go after voltage and amp readings again.

LH, I see your posts is asking the same questions as me because something doesn't add up to the way we think it should. I was hoping with bumping the thread with the theoretical output Lumens someone would swoop in and adjust my attitude.

To answer your first questions the voltage reading was 7.95 and would drop in to 7.9. After fooling with these surprises for a while I got it to drop to 7.83 but I think that was longer than than your 90 second test. I will watch the watch closely. Anyone that can suggest improvements to slugging it out with my DMM let me know. I have a cheapy DMM that I will use too to back up my main meter, a Chinese Fluke clone.

I am waiting with anticipation for AW's new cells, they should take care of this with no problem.

missionaryman · Dec 24, 2006

Just for the record I have been amazed at how much current 2 x 18650 can supply, firstly I used AW's 2200's now I'm using battery station 2400's in the ROP and both supply 4.3A at start up and are still holding 4.19 after a few minutes (bit of a guess but it was more than one minute anyway).
6 Sanyo 2500 AA's drop to well below that and the beam yellows up a bit, only my 6 4500mah C cell ROP can hold those currents.

I think LiIon 18650's are more powerful than most people would think, in a side by side test a 2 x 18650 ROP was brighter than a 6 x CBP1650 ROP with switch fix.

Bob_G · Dec 24, 2006

Hmm, those voltage readings sound exactly like what you'd expect, under the conditions you describe, for a no load reading. How are you testing for voltage? Are you taking it at the pins with the light on, or using a resistor, or just taking it at the bi-pin holder? I think once you get a proper reading you'll be surprised at how much lower it is, mostly because even at that lower reading, the 5761 still looks great

What I've been doing is making a little loop with a small pair of needle nose on two little pieces of wire, then hooking them on the pins and crimping a bit to secure. Put in the bulb, hook up alligators to the wire, turn on the meter, put the mess under my desk to protect my eyes, then turn on the light. With the meter already on it gives you both hands to manipulate the light and hold the wires stable. I guess there's plenty of ways to do it, but this has been working for me.

Northern Lights · Dec 24, 2006

I am itching on the time, waiting for the batteries to set these next 4 hours, tick, tock.. I will try it again.

Yes, I took the V off the pin and Amps out of the circuit when on. That is why it doesn't add up.

Here is the 18650 thread, nobody has a good grip on this relatively new product.
https://www.candlepowerforums.com/threads/142805

That is like when you posted the 1160 new hot wire (man you drive it!), no one, ah, "hoodathunkit?"

Northern Lights · Dec 24, 2006

I found the Gremlin! Anyone wishing to inflate their claims without using the "exagerated wind" technique then I have the solution. I will gladly loan them my Fluke clone DMM as it is reading a lot of things high now.
I went and got another meter. I found some problems with the original one which is fairly new and in the end the meter finally blew its fuses.
Oh, yeah back to the 2CM61 LE.
The 18650s appear to be reading off the charger after settling down some at 2400 mAh. Since most battery claims are inflated, this is good.

The light drew 5.3 amps
Turning the light on the display would start around 7.9 and then immediately the voltage dropped very quickly to 7.1-7.0, down to 6.9 volts at the bulb and then started to decline very gradually, around 1 minute I terminated at 6.8 because the leads were coming off and this meter does not have a high enough degree of accuracy to matter.
38 watts is more like it.

Obviously the light does start out within the first minute close to that 1000 Bulb-Lumens and could be over if the batteries are recently off the charger but that voltage drop brings it down falling below 900 bulb-lumens when the voltage drops below 7.1 volts.
Next test is to get a reliable meter again and see how a prolonged run of several minutes really adds up.
Thanks for the interest and help, Guys. I'll reconnect after the holiday and the best to you.

Modded 2C M@g, (2cM61), 1331 Torch-Lumens

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